import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/getParameter")
public class GetParameter extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        resp.setContentType("text/html; charset=utf-8");

        // 通过HttpServletRequest 对象的getParameter方法获取对应参数的值， 如果参数不存在 则返回null

        String userId = req.getParameter("userId");
        String classId = req.getParameter("classId");
        resp.getWriter().write("userId: "+userId+", "+"classId: "+classId);

    }


}
